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What tonearm will better mine?

I have been running a 12" Jelco SA750L with an upgraded Decca Super Gold on a Garrard 401 for a few years. I'm happy with the sound and happy with my pre, power and speakers. (Croft 25R, EICO HF35s, -good tubes, Quad 57).
I keep hearing that my tonearm is a weak link even though it sounds pretty awesome to me. What would it take to replace the Jelco and make a significant improvement? What should I expect to hear better? Would I have to drill the massive plinth? Thanks.
128x128noromance
andrei_nz
106 posts
 
One tweak that I have found to be very worthwhile with my 750D has been the Ammonite Acoustics mounting collar, which eliminates the slight slop in the OEM collar and ensures correct positioning of the arm as it relates to azimuth. Very important with more exotic stylus profiles. 

I also recently changed out the stock Jelco headshell to a Yamamoto HS4 Carbon Fiber headshell. This was a real eye (or ear) opener: pretty substantial improvements across the board in information retreival, overall presentation and dynamics. A no brainer for about $100 U.S. on ebay.
I have to second the Ammonite Accoustics mounting collar.  The brilliant thing about these is that he makes them from ebony!  Expensive? maybe, but not in "Hi-Fi" terms.  The great thing about ebony is that it is used to make musical instruments, oboes, clarinets for example.  All materials have a resonance, but the resonance of ebony is benign.  Match that with a Yamamoto Ebony (or Mpingo) headshell and you will get a real benefit.  Also there is the 'Shuggie Collar' as a tweak to the Jelco.  They are sold by ammonite accoustics.  The only downside to the Jelco is that the grub screw on the mounting collar is not centered.  A bit like rolling a log but pushing it with your foot at one end instead of the centre - it might go off course.  So great care is required in set up.  The aftermarket collar is is essential in mounting the arm to a Technics and I guess the same can be said for a Garrard.  The last tweak is silver rewiring.  I am not really a 'cable guy' but I do believe the smaller the signal the more important it is to have good a good cable.

As you may have guessed I am a Jelco owner.  If I was building another TT I would not go for a VPI or 'modern' tonearm.  I might even plonk another Jelco on it.  My other thought would be an SME M2-12.
bdp24's avatar
bdp24
4,908 posts
 

The old Decca's were extremely variable, each one needing to be loaded to match it's particular performance. The current London's are much more consistent, and can be loaded according to builder John Wright's recommendations.

Noromance, the Decapod (why it is spelled with only one c I don't know) offers a couple of improvements. The "Pod" makes the cartridge less microphonic, being a thick slab of aluminum that replaces the much less non-resonant thin piece of tin that is the stock top plate of the cartridge. The Pod makes unnecessary the stock cheesy red plastic mounting bracket, a major source of weakness in the mating of arm and cartridge. The Pod is threaded, allowing for a tight direct fitting to the arm's headshell. The discarded plastic mount also contains the cartridge's output pins, which connect to thin strips of brass or copper (like the blades on the battery connections inside a flashlight) on the back of the cartridge body, necessitating an extra break and connection in the signal path. With the substitution of the Decapod for the stock mount, the output pins are on the cartridge itself, a huge improvement with a signal as low in voltage as that of a cartridge's, even the Decca's 5mV!

I believe the Decapod is available as a DIY part, or you may return the cartridge to have it installed by John. He will at the same time adjust and test the cartridge, returning it with a performance test report if I'm not mistaken. I wouldn't have a Decca without the Decapod!

noromance's avatar
noromance OP
1,780 posts
 
Thanks everyone.
bdp24, The name may be a play in decapods - animals like crabs - I guess the tight grip...
Wasn't the red plastic part of the damping? I like the idea of a solid base for the Decca. Have you heard the Decapod upgrade? My Mk.Vll has already been to JW for a Paratrace tip which was a major upgrade. I'll shoot him an email when it's due a retip. Thanks.

bdp24's avatar
bdp24
4,908 posts
 

The red plastic mount wasn’t designed for damping, but merely for mounting the cartridge, and perhaps for easy switching between models---elliptical, spherical, the version for 78’s. The cartridge originated in the 1950’s, long before people were as concerned with damping resonances as are we now. That mounting design exhibits a fair amount of flex, allowing relative motion between cartridge and headshell, obviously not a good thing. People have tried all sorts of DIY remedies, the most common being Plasticene, Mortite, Blutack, modeling clay, and other putty-like materials wedged into the space between the top of the cartridge and the bottom of the mount, to prevent that motion. The Decapod is a far better solution, making the cartridge as tightly secured to a headshell as any "normal" one. I ordered my London Super Gold Mk.VII with the Decapod already installed, but my earlier Decca SG originally had the stock mount. I sent it back to John for him to install. Yes, definitely worth the money!

The Paratracer tip is universally lauded by Decca/London owners, and when I need a retip I’m definitely going to have John install it on my London.

2channel8
634 posts
 
For those who don't want to shell out for the MINT protractor:

Conrad Hoffman wrote:Ok, I admit it. I tested this on the unsuspecting folks at the asylum first. After a few revisions, here's my cartridge arc alignment template and strobe disk generator. It's far smaller than bitmaps of the same thing, plus you can choose your specific pivot-to-spindle distance, groove radius and alignment strategy choice. It also prints pretty darn nice strobe disks. Freeware, no viri, no strings attached. Please let me know what you think.

http://www.conradhoffman.com/chsw.htm

noromance, 

I may have missed it; but have you played with damping fluid? I have a SA750 clone, the Sumiko Premier MMT and like you I sometimes get upgradeitis. Then I buy a new phono cable or something and come to my senses. The Jelco may be underappreciated by some because of it's modest price; but I have found it to better many more expensive arms. If I had $3,000 to spend improving my system, I certainly wouldn't spend it all replacing my Sumiko!
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